This Small Business Innovation Research (BSIR) Phase I project will address the need for a trace benzene vapor sensor for ambient air. Benzene is a carcinogen and significant Mobile Source Air Toxic (MSAT) released during incomplete combustion of fossil fuels, and is commonly emitted from motor vehicles and many industrial sites. Entanglement Technologies proposes to determine the feasibility of developing a benzene vapor sensor with sensitivity better than 100 pptv in 30 minutes based on the combination of cavity ring-down spectroscopy (CRDS) and diffusion time-of-flight (DiTOF). This combination allows the use of the extremely sensitive CRDS technique to detect large molecules that cannot be distinguished spectrally using CRDS alone. The Phase I project will develop a prototype detector to evaluate and demonstrate the critical technologies.
The broader/commercial impacts of this research are the development of a sensor with the ability to detect benzene and map its dispersal into the environment. This will directly impact health hazard mitigation, liability exposure reduction, and reduced regulatory compliance costs in numerous industries. The improved sensitivity and reduced cost of the sensor indicate strong market demand for the sensor. The technology platform will be readily extended to a wide variety of other air toxics including toluene, ethyl-benzene, and xylenes. In the long term, this technology will be applied to biomedical science, industrial process monitoring, environmental remediation and explosives detection. Diffusion-based selectivity will allow separation and quantification of the many hydrocarbon gas components in human breath, that are useful for non-invasive diagnosis of disease.
Introduction and Intellectual Merit The goal of this SBIR Phase I grant was to demonstrate the feasibility of combining a novel molecular diffusion technique with Cavity Ring-down Spectroscopy (CRDS) in a laboratory prototype for the purpose of identifying and characterizing air toxics, including benzene, toluene, ethylbenzene, xylenes (BTEX), and 1,3-butadiene, in near real-time with sensitivities approaching 100 pptv. Entanglement Technologies’ work on this NSF SBIR served to further the research and development of extremely sensitive and selective chemical analyzers towards a compact product employing advanced spectroscopic and molecular diffusion techniques, which had previously been confined to use in fixed laboratories with the aid of expensive instrumentation and labor-intensive sample gathering. Results We have demonstrated the feasibility of a high performance benzene and toxic VOC detector with outstanding real-time performance and capabilities. We have retired the relevant technical risk, proving exceptional laser and optics performance, multi-species detection, and preconcentration. An existing system has been adapted for this project. This system has shown detection capabilities within a factor of ten of its theoretical limit. The transition from the laser wavelengths used in this system to the shorter wavelength lasers tested as part of this phase will allow us to achieve the projected performance. The high dynamic range and linearity of our optical detection technique ensure that performance will scale in proportion to the optical absorption cross sections of the analytes. Broader Impact As global industrialization continues to accelerate, the release and dissemination of toxic industrial byproducts within Earth’s atmosphere, water, and soil increasingly threaten health and well-being. Enabling wider and deeper access to actionable atmospheric data—i.e., improving our ability to identify and monitor changes in atmospheric composition, illuminating the contents of the air we breathe—will afford humanity the ability to control and mitigate proliferation of health-threatening toxics in a cost-effective fashion. The technology developed through this SBIR will do exactly that. Furthermore, the underlying technology platform is readily adapted to the real-time analysis of a broad range of additional toxic chemicals, industrial pollutants, and other harmful chemicals.
